The Wideband Code Division Multiple Access (WCDMA) protocol is used by wireless communications systems, for example, third generation (3G) cellular mobile communication systems.
A WCDMA device may include a Rake receiver to receive signals from many multi-paths and to combine the received signals into a combined signal.
The Rake receiver may include a path searcher, which may use a set of signal samples to select a pre-determined number of dominant paths. The efficiency of the Rake receiver may depend on the selection of dominant paths and on a calculation of time delays for the dominant paths, e.g., a more accurate selection of dominant paths and more accurate calculation of time delays will result in higher Signal to Interference Noise Ratio (SINR).
In some conventional systems, the Rake receiver may use a Delay Locked Loop (DLL) to adjust synchronization of each of the dominant paths with a sub-chip resolution, Tc/8, wherein Tc is the chip period. In conventional path searchers, some dominant paths, for example, strong paths having relatively high amplitudes, may be undesirably ignored by the path searcher and may, thus, remain undetected. This may result in a lower efficiency, e.g., lower SINR. Other disadvantages of some conventional path searchers include a time shift of the detected paths, a relatively low and/or constant sub-chip level resolution of the delay of multi-paths, lack of information regarding path amplitude and/or time delay of selected paths. Additionally, some prior art path searchers involve complex hardware implementation.
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